以前装双系统只要先装Windows7，然后再装Centos7的话，grub会自动添加原有的Windows7系统。不过在新的Centos7中需要手动修改、
步骤如下
$ sudo vi /etc/grub.d/40_custom #!/bin/sh exec tail -n +3 $0 # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the ‘exec tail‘ line above. menuentry ‘Windows7‘{ set root=(hd0,1) chainloader +1 } $ grub2-mkconfig -o /boot/grub2/grub.cfg $ reboot
原文：http://www.cnblogs.com/oskb/p/4615581.html